Not applicable.
Not applicable.
1. Field of the Invention
The invention relates to a device for sterilizing water flowing through a sanitary appliance, having
a) a housing, which comprises an inlet and an outlet for the water;
b) a UV lamp, which is disposed inside the housing and the radiation of which is directed towards the water flowing through and optionally towards a filtering apparatus likewise disposed in the housing;
c) a power supply circuit for the UV lamp;
d) a device for producing a switch-on signal for the power supply circuit of the UV lamp;
e) a solenoid valve, which is situated in the fresh water supply conduit and energized by a valve driver circuit;
f) a control circuit, which is connected to the valve driver circuit of the solenoid valve, the power supply circuit for the UV lamp and the device for producing a switch-on signal for the UV lamp and is so designed that it activates the driver circuit for the solenoid valve only with a specific time delay after the power supply circuit for the UV lamp;
g) a valve, which is operable by the user, in the fresh water supply conduit;
h) a pressure sensor situated between the solenoid valve and the user-operable valve in the fresh water supply conduit.
In recent years the dangers arising in the field of sanitation from water contaminated with micro-organisms, in particular bacteria, amoebae or other monocellular organisms, have become ever clearer. For said reason, increased importance is being attached to water sterilization. In said connection, there have been reports of experiments to sterilize flowing water through exposure to UV light, which is of a wavelength suitable for killing micro-organisms carried along in the water. To extend the retention time of said micro-organisms in the region of the UV lamp, an additional filtering apparatus may be used.
2. Technical Field
In the devices known from said experiments, the UV lamp was activated when the water flow is set in operation, e.g. by means of a mechanical switch which was mechanically connected to the operating element of the valve controlling the water flow. However, since the UV lamp upon activation does not immediately operate at full radiant power, with said known devices the sterilizing capacity in the initial phase after switching-on was inadequate.
A generic apparatus is known from DE 39 24 350 A1. There, a switch, which via a control circuit 2 activates a UV lamp, is used as a device for producing a switch-on signal.
Further devices for sterilizing water with the aid of a UV lamp, which use control circuits which activate the valve driver circuit for the inlet valve in the water supply conduit with a time delay compared to the switching-on of the UV lamp, are known from GB 21 27 177 A, FR 24 14 480 A and DE 38 40 276 A.
Upon the occurrence of a xe2x80x9cswitch-on signalxe2x80x9d indicating the request of a user to draw off water, the water flow is not immediately set in operation. Rather, the control circuit first ensures that the power supply circuit for the UV lamp is activated. The UV lamp is therefore ignited and comes within a few seconds up to operating temperature, after which its operating state is stabilized and the full luminous capacity is attained. It is only then, i.e. after a specific time delay, that the control electronics also activate the valve driver circuit for the additional solenoid valve provided according to the invention; it is only then that water starts to flow and then encounters inside the housing of the device a UV lamp which is fully activated and hence operating at maximum sterilizing capacity.
In the known sterilizing devices, the switch-on signal for the UV lamp is produced by means of a switch which is to be separately operated. If, e.g. out of ignorance, said switch is not operated, it is impossible to draw off water.
The object of the present invention is to refine a device of the type described initially in such a way that automatic activation of the UV lamp is guaranteed in response to a draw-off request by the user, which is effected in the manner customary with sanitary appliances through opening of the user-operable valve in the fresh water supply.
Said object is achieved according to the invention in that
i) the solenoid valve is disposed upstream of the valve, which is operable by the user, in the fresh water supply conduit and that
j) a signal of the pressure sensor ascertaining a pressure drop is utilized as the switch-on signal for the power supply circuit.
The solenoid valve therefore serves simultaneously as part of the device for producing a switch-on signal. Said device uses, as a xe2x80x9ccontrolled variablexe2x80x9d indicating the request of the user to start and end a dispensing operation, the pressure inside the portion of the fresh water supply conduit lying between the additional solenoid valve and a valve operable by the user. By xe2x80x9coperable by the userxe2x80x9d is meant not only the direct mechanical operation, e.g. by means of the lever of a single-lever mixer, by the user. In the context of the present invention, a solenoid valve actuated without contact is also xe2x80x9coperable by the userxe2x80x9d.
The time delay between switching on the power supply circuit for the UV lamp and activating the valve driver circuit for the solenoid valve should be, say, in the order of magnitude of 0.2 to 3 seconds.
It is advisable to provide the device according to the invention with a display, which is activated immediately upon the occurrence of a switch-on signal. When said display lights up, the user knows that the device is working even though the water does not start to flow straightaway. This prevents irritation on the part of the user.